deboni@fernando.llnl.gov (Tom DeBoni) (11/10/90)
I'm interested in high speed modems, and I've been reading about new standards proposals for very high speed operation over standard phone lines. The only trouble with all this is finding serial port devices that will go that fast and writing system software to support them.Tthis naturally leads me to wonder just how fast the serial ports in Macs will go. I've seen measurements indicating that Macs have trouble keeping up with 19,200 bps data rates, but I believe this is due to software, not hardware. I know that my Mac IIcs can't keep up with my Telebit T2500 in either of its two fastest modes (PEP and V.42bis) with color turned on, and that it does much better with color turned off. Anybody out there in netland know how fast Apples modem port can operate, and how fast the system software can send and receive data? Are there any plans to make them faster? Will the nuBus serial cards that can be used with the Comm Tool Box support any higher speeds? I'm thinking of the proposed ultimate modem standards, which have numbers like 56,000 bps, 78,000 bps, and even 100,000+ bps being bandied about in them. if these things come about, it sure would be nice to be able to use them. And for that matter, what of the possibility of an ISDN card that can offer all of the initial phase speed of 144,000 bpc (to say nothing of the ultimate planned T1 speeds of 1.544 Mbps)? Tom DeBoni
russotto@eng.umd.edu (Matthew T. Russotto) (11/10/90)
In article <85816@lll-winken.LLNL.GOV> deboni@fernando.llnl.gov (Tom DeBoni) writes: >I'm interested in high speed modems, and I've been reading about new standards >proposals for very high speed operation over standard phone lines. The only >trouble with all this is finding serial port devices that will go that fast >and writing system software to support them.Tthis naturally leads me to wonder >just how fast the serial ports in Macs will go. I've seen measurements >indicating that Macs have trouble keeping up with 19,200 bps data rates, but The mac (II series, anyway) will easily keep up with 19,200-- that's the fastest I have run it, and usually it is the other side (Big Ugly Vax, or perhaps an MNP 5 modem) that gets overrun, unless I try to do other processor intensive things-- like display at the same time, or use other programs under multifinder. (what I mean is that you can't do text captures at 19200, or even 4800 with 8-bit color on. But file transfers that do not echo to screen work fine). (And before you text-based computer freaks jump on the mac for this, neither will an IBM-PC AT, once it starts scrolling) -- Matthew T. Russotto russotto@eng.umd.edu russotto@wam.umd.edu Tax the rich, and feed the poor -- until there are, rich no more.
cs325ax@ux1.cso.uiuc.edu (David Hull) (11/10/90)
russotto@eng.umd.edu (Matthew T. Russotto) writes: >(what I mean is that you can't do text captures at >19200, or even 4800 with 8-bit color on. Depends on your terminal emulator. Versaterm keeps up with the full speed of my TrailBlazer Plus (12000 baud or so) with my CX in 8-bit color mode. MicroPhone II also seems to do ok. -David
rfl@oddjob.uchicago.edu (Bob Loewenstein) (11/12/90)
> I'm interested in high speed modems, and I've been reading about new standards > proposals for very high speed operation over standard phone lines. The only > trouble with all this is finding serial port devices that will go that fast > and writing system software to support them.Tthis naturally leads me to wonder > just how fast the serial ports in Macs will go. I've seen measurements > indicating that Macs have trouble keeping up with 19,200 bps data rates, but > I believe this is due to software, not hardware. I know that my Mac IIcs can't > keep up with my Telebit T2500 in either of its two fastest modes (PEP and > V.42bis) with color turned on, and that it does much better with color turned > off. Anybody out there in netland know how fast Apples modem port can operate, > and how fast the system software can send and receive data? Are there any > plans to make them faster? Will the nuBus serial cards that can be used with > the Comm Tool Box support any higher speeds? I'm thinking of the proposed > ultimate modem standards, which have numbers like 56,000 bps, 78,000 bps, and > even 100,000+ bps being bandied about in them. if these things come about, it > sure would be nice to be able to use them. And for that matter, what of the > possibility of an ISDN card that can offer all of the initial phase speed of > 144,000 bpc (to say nothing of the ultimate planned T1 speeds of 1.544 Mbps)? I have been using high speed modems for over a year with a mac II. The modems are both Microcom V.32c and V.42bis with MNP9 and MNP10 protocols, respectively. The macII talks to the modem via the modem port at 38400 baud with NO handshaking. Most of the data is input to the mac, with small control strings going out of the mac. The data returning is binary, sometimes as big as 1.4MBytes. The only problem I have had has come from having AppleTalk ON...and the more Appletalk related things running (such as TOPS). I asked about this to MACDTS and received this reply in part: > There are no guarantees about data acquisition whenever AppleTalk is being > used, or even turned on. While the Mac is receiving an AppleTalk packet, > interrupts are disabled for the entire length of the packet. This means that > if the largest possible AppleTalk packet was sent, it would take about 26 > milliseconds to receive the packet. Asynchronous serial data transferred at > 9600 bps would take about 1 millisecond to transmit. Simple math says about 26 > characters could potentially be lost if a 603 byte packet was received. This > is very realistic especially when there are routers on the network which send > out large routing table maintenance packets (RTMPUs). So, If I turn AppleTalk OFF, I have had no problem (with or without handshaking!). Once AppleTalk is turned on, I get an error=-89, with 1 to 3 bytes lost. I also am hoping to use a Nubus board that will alleviate this problem and go faster. I am beta testing a DigiChannel multiserial board that might do the trick (and also communicate >56000baud). I'll post my results.
jack@Taffy.rice.edu (Jack W. Howarth) (11/13/90)
Bob,
Wouldn't going to a hardware handshaking cable and using hardware handshak-
ing in your terminal program help with your AppleTalk problem. It certainly
is the best way to use a MNP5 or v42bis modem because the actual data transfer
rate is going to be higher at cpu<>modem than at modem<>modem.
Jacknews@macuni.mqcc.mq.oz (USENET News System) (11/15/90)
>I'm interested in high speed modems, and I've been reading about new standards >proposals for very high speed operation over standard phone lines. The only >trouble with all this is finding serial port devices that will go that fast >and writing system software to support them.Tthis naturally leads me to wonder >just how fast the serial ports in Macs will go. I've seen measurements >indicating that Macs have trouble keeping up with 19,200 bps data rates, but >I believe this is due to software, not hardware. I know that my Mac IIcs can't >keep up with my Telebit T2500 in either of its two fastest modes (PEP and >V.42bis) with color turned on, and that it does much better with color turned >off. Anybody out there in netland know how fast Apples modem port can operate, From: s8925188@mqcomp.mqcc.mq.OZ (Philip Craig) Path: mqcomp!s8925188 I have run *both* serial ports on a plain Mac II at 19,200 error-free, both ports on an SE/30 and Mac IIx at 38,400bps error-free, and both ports on a Mac IIfx at 57,600 error-free. The trouble is finding good software to keep up at these speeds (I wrote my own). I guess that a Mac servicing only one port (my application always used both at once) would be able to keep up at higher speeds than this. Note also that LocalTalk runs the port happily at approx 238,400bps and manages....even on the old 128K Macs. >and how fast the system software can send and receive data? Are there any >plans to make them faster? Will the nuBus serial cards that can be used with >the Comm Tool Box support any higher speeds? I'm thinking of the proposed >ultimate modem standards, which have numbers like 56,000 bps, 78,000 bps, and >even 100,000+ bps being bandied about in them. if these things come about, it >sure would be nice to be able to use them. And for that matter, what of the >possibility of an ISDN card that can offer all of the initial phase speed of >144,000 bpc (to say nothing of the ultimate planned T1 speeds of 1.544 Mbps)? Well the ISDN card won't be going through the built-in serial ports, so that is not an issue. It will be limited by processor speed and the bandwidth of either SCSI or NuBus or the PDS, none of which should be a problem. ------------------------------------------------------------------ I've got this terrible pain in all the diodes down my left side... ACSnet ( s8925188@mqcomp.mq.oz ) UUCP ( uunet!munnari!mqcomp.mq.oz!s8925188 ) Internet ( s8925188%mqcomp.mq.oz@uunet.uu.net )
merlyn@digibd.com (Brian Westley (Merlyn LeRoy)) (11/17/90)
jack@Taffy.rice.edu (Jack W. Howarth) writes: >Bob, > Wouldn't going to a hardware handshaking cable and using hardware handshak- >ing in your terminal program help with your AppleTalk problem? This isn't Bob, but I'm the guy at DigiBoard writing the driver for the NuBus serial card that Bob is betatesting... The problem with the mac serial ports is lack of control lines; mac ports only have one input (CTS) and one output (DTR). With high-speed modems, you generally need one input for Data Carrier Detect and one for hardware flow control. With only one input line, you must forego DCD or flow ctrl... Our serial card has DTR & RTS outputs, and DSR, DCD, CTS, and RI inputs. I am also adding configurations where you can force hardware flow control on, using RTS/CTS, and let the mac see DCD come in as CTS (for example). I hope to hit 57600 baud on all eight ports going full-bore. Our A/UX driver can keep up at 38400, but I've improved the core tx/rx routines since then. --- Merlyn LeRoy ..uunet!digibd!merlyn
Lloyd.Woodall@f31.n343.z1.FIDONET.ORG (Lloyd Woodall) (12/16/90)
Tom, the Mac CAN keep up with a Telebit at 19.2k. I am guessing that you are talking about video refresh and not file transfers. I have the Creative Solutions Hurdler Nubus miltiport serial card. (4 ports). I am a beta tester for this and it will support 38.4k baud with 3 channels driver and 19.2k baud with all 4 channels driven simultaneously. It also offloads some input/output tasks from the cpu. I run a 5 node Hermes BBS with it and I get over 1650 cps on my HST Dual Standard (Z-modem w/compressed files) and about 1450 cps with the T2500. And this is with simultaneous downloading on all other lines. This card registers itself with the Mac Comm Toolbox and, unlike the Mac's own serial ports, will support a DTR hangup feature (BBS carrier detect cable) AND CTS hardware handshaking. For literature on this card call Creataive Solutions at 800-367-8465. BTW, I have been a beta test site for other multiport hardware, but Creative Solutions is the best. $299 & $379 for 2 or 4 port cards respectively. -- Lloyd Woodall via cmhGate - Net 226 fido<=>uucp gateway Col, OH UUCP: ...!osu-cis!n8emr!cmhgate!343!31!Lloyd.Woodall INET: Lloyd.Woodall@f31.n343.z1.FIDONET.ORG